N. Doukyu et R. Aono, PURIFICATION OF EXTRACELLULAR CHOLESTEROL OXIDASE WITH HIGH-ACTIVITY IN THE PRESENCE OF ORGANIC-SOLVENTS FROM PSEUDOMONAS SP. STRAIN ST-200, Applied and environmental microbiology, 64(5), 1998, pp. 1929-1932
Extracellular cholesterol oxidase of Pseudomonas sp. strain ST-200 was
purified from the culture supernatant. This oxidase contained bound f
lavin and was categorized as a 3 beta-hydroxysteroid oxidase, converti
ng 3-hydroxyl groups to keto groups. The molecular mass was 60 kDa. Th
e enzyme was stable at pH 4 to 11 and active at pH 5.0 to 8.5, showing
optimal activity at pH 7 at 60 degrees C. The Michaelis constant of t
he ST-200 cholesterol oxidase was lower than those of commercially ava
ilable oxidases. The cholesterol oxidation rate was enhanced 3- to 3.5
-fold in the presence of organic solvents, with log P-ow values (parti
tion coefficients of the organic solvent between n-octanol and water),
in the range of 2.1 to 4.2, compared with that in the absence of orga
nic solvents.